What is killing the 6203 DD Bearings?

[Coldfinger]

The general theory seems to be that side loading or overloading is killing the bearings but are we sure?

Yesterday I took a peek in my 2010 M8 800 miles. The 6203 outer seal and cage were shot but the bearing still seemed to turn rather freely. This seems to be consistent with most of the other reports. Nobody suspected a bearing problem till they pulled it apart and looked.

Cat and a lot of dealers are claiming no knowledge of bearing problems, maybe because people are fixing themselves OR maybe because the sleds don't have enough miles where the bearing has totally failed, thus most owners are not aware there is a problem.

Could it be a lubrication issue? Maybe the sealed bearings are beginning to fail because of lack of lube, then, once the bearing begins to fail it takes out the cage which knocks out the seal, then that allows some DD lube to enter and then the bearing continues to work for hundreds or thousands more miles before total failure because it is finally getting oil lube from the DD oil??

Could it be a speed rating issue in that the bearing is turning faster than it is rated?

 

[Klimbing Kitty]

I was told the other day that it is because the bearing is not all the way on the shaft. It appears to be seated correctly but it is like 2mm short of being on the right way. This is the factories fault some will be on correctly and some won't. the only way to know is if you pull the diamond drive apart before any miles are put on the sled.

 

[Coldfinger]

The shaft extends 1mm beyond my bearing. The bearing appears to be seated against the spacer and the spacer doesn't rotate freely (not sure if it is pressed on or not).

I just spoke with Motion Industries (bearing supplier) and they said the OEM bearing Peer 6203 RLD does not appear to be a low friction contact seal bearing according to their x-ref chart for NSK.

If that is true maybe that is part of the problem, though I would think the bearing speed rating would take that into account.

 

[Flange]

Thats an interesting theory Coldfinger although completely opposite of why they say the seal is there in the first place. Its supposed to keep oil in the bearing, but who knows for sure if its actually doing that. Maybe your right. Another season of riding will help figure it out.

 

[Coldfinger]

Flange - I believe the sealed bearings have grease inside. From what I've read on bearing specs, greased bearings have a lower speed rating than those running in oil.

That is why I ask about the speed issue - I have no clue how many rpms these bearings turn but the OEM is rated at 18,000 in grease. Quite a few of the aftermarket bearings seem to be 12,000-15,000 except that SKF has one that is 19.000.

Interesting note - the 4203 & 5203 units I've seen are rated for 12-15,000 rpm, and BDX recommends the 5203 so maybe the rpm isn't a concern as long as it is 15,000 ish.

 

[papdog7]

is it not the only sealed bearing in there? i have seen the rest of them are open sided bearings? to me that makes no sense?

 

[diggerdown]

viberation takes bearing cages out...maybe ruff or loose gear mess.

 

[kraftymike]

I talked to a reliable source who told me that some of the recent cat tunnels produced were made too narrow. This is what is causing the excessive side loading, and why the trackshaft needs .055-.075" taken off to correctly repair.

 

[Coldfinger]

I was aware of potential side loading when I unbolted the cover and my cover didn't pop loose like I had read so I figure there must not be much side loading on my 2010, but who knows, maybe the gasket sticking held it in place.

Vibration is possible. I suppose the 5203 bearing and the 4203 can handle that much better.

 

[kraftymike]

I was aware of potential side loading when I unbolted the cover and my cover didn't pop loose like I had read so I figure there must not be much side loading on my 2010, but who knows, maybe the gasket sticking held it in place.

That is great news for you. Sounds like you got one the good ones. Haven't done mine yet, so I will keep my fingers crossed.

 

[waycooljr]

I have been trying to keep up with all the chat on the Diamond Drive issues. I am confused to what bearing to actually go with. I have heard the numbers of 6203 ,5203, 4203, and some of the numbers have been superceeded to a new number? Doesn't sound like anyone is getting much help from Cat, except the original oem part. Are these the same bearing numbers for the 2010 HCR's or am I making this more confusing that what it should be? Wish I had the gonads enuff to take a new sealed bearing, remove the seals, install it, and fill the DD with more lube than recomended. That would cure the theory of any lack of lube issues!! I'm just say'n!!!!!!!!

 

[sledhead ut]

Wish I had the gonads enuff to take a new sealed bearing, remove the seals, install it, and fill the DD with more lube than recomended. That would cure the theory of any lack of lube issues!! I'm just say'n!!!!!!!!

I did it in my wifes 09 M8 Sp. Pulled the seals off. I feel the seals allow the bearing to burn off internal lubricant and build excessive heat. Too many stories about blown cages. No seals and extra lube may be the answer to make the stock $4 bearing work. If it blows I'll be the first to admit and inform.

 

[kraftymike]

I have been trying to keep up with all the chat on the Diamond Drive issues. I am confused to what bearing to actually go with. I have heard the numbers of 6203 ,5203, 4203, and some of the numbers have been superceeded to a new number? Doesn't sound like anyone is getting much help from Cat, except the original oem part. Are these the same bearing numbers for the 2010 HCR's or am I making this more confusing that what it should be? Wish I had the gonads enuff to take a new sealed bearing, remove the seals, install it, and fill the DD with more lube than recomended. That would cure the theory of any lack of lube issues!! I'm just say'n!!!!!!!!

The replacement bearing used to fix the problem is actually the same bearing that BDX originally engineered for the original M7 DD. I can't figure out why cat would gone away from this proven, trouble free bearing unless this was their solution for the narrow tunnels.

 

[clutch]

BDX posted in another thread that the bearing is sealed because where the brg is located, centrifugal forces don't allow lube oil to stay in the bearing. I would be leary of removing seals and running it.

 

[Johnmaster]

I think they got away from the bearing when they engineered reverse into the box on their own. They ran out of space and figured the single row bearing would work.
The theory I am going with is if the stock bearing made it 4000 miles, a standard replacement should do roughly the same, no reason to change. For the guys with under 1000 mile failures you must have something excessively wrong. I don't think the bearing is as much at fault as is the environment it is operating in. Hopefully by the end of this season more info comes out on this topic and a better solution is found. I had 4200 miles on my 09 crossfire and the bearing wasn't new but it had plenty of life left in it, just a little broke in...the design should work but apparently for some it doesn't.

Has anyone been measuring these supposed narrow tunnels? Mine is as close to 16" inside as I can measure with a steel rule. 290 miles and was as good as new.

 

[Coldfinger]

Seems odd to me that there are a lot of 6203 bearings which nearly failed. They lost the bearing cages and took out one or both seals, then they appear to keep going even though one would think they would fail in short order once the cage and seal is gone.

Do they keep going because they are finally getting some lube?

Not knowing at what point the cage and seal is lost makes it hard to surmise anything. Maybe all these discoveries were lucky and caught the bearing before it grenaded.

This is why I question whether an open bearing may be better, because I doubt we are all so lucky as to caught the bearing just after the cage and seal failed.

I'm not saying to run without seals, but it does seem like it might help. We need more feedback from people who have logged miles with the various replacements.

 

[F_ast]

One thing I have noticed in bearings lately (bearings in general here), is when looking at the bearing seals on domestic vs. Chinese, the Chinese bearing seal clearance to outer bearing face is at least 2 times larger than that of domestic made bearings. I was looking at a new brand new 6205 skid bearings, and the difference was very noticeable. Thinking the china stuff has a sloppier fit and or less quality standards. This clearance difference is enough to be knocking them out.

 

[tranquillicer]

cheap junk

One thing I have noticed in bearings lately (bearings in general here), is when looking at the bearing seals on domestic vs. Chinese, the Chinese bearing seal clearance to outer bearing face is at least 2 times larger than that of domestic made bearings. I was looking at a new brand new 6205 skid bearings, and the difference was very noticeable. Thinking the china stuff has a sloppier fit and or less quality standards. This clearance difference is enough to be knocking them out.

My buddy took his brg to the local napa dealer and first thing he said was"their junk". Replacement brg apparently is not how ever cause its gonna cost....get this...$43.

 

[Coldfinger]

The 6203 bearings are much more common. The word commodity was used by one supplier I spoke with.

The 5203 is not so common and the 4203 makes a lot of suppliers scratch their head but these are both in the $40 price range according to my quotes. Not sure how BDX can sell them for $15 (5203).

 

[skidooboy]

one thing i did (do) when i replace any bearing is, remove the lip seals, add more grease to the bearing case on both sides, and replace the seals. if you have never taken the lip seals off a NEW bearing, it is eye opening to say the least. they use very little grease to pack the bearing from the mfgr. better safe than sorry, check yourself, and add more for your own saftey, longevity, and piece of mind.

did this with both our 09 m8's, no problems after inspecting and oil change after last seasons riding was over. ski